Is it possible to design an array with N elements with each element resonating at a different frequency?

Hi,

I want to design an array with N elements (say N = 5), and each element is excited with a different frequency.

In a practical scenario, let us consider a case of a dipole antenna, we give an excitation at the feed location with some voltage value at a specified frequency (say V = 1 volt, and f = 1 GHz).

In the case of an array, suppose we have 5 dipole elements, so considering a practical scenario, I want to excite each element with same voltage V= 1 volt, but the frequency is different for each of them.

Now considering the inbuilt MATLAB array functions such as linearArray, circularArray, or conformalArray; I want to do the same described above.

I doubt lies on the point that, for all these array functions we plot the radiation pattern at a given frequency which is fine for an array with all elements excited at a fixed frequency. But how do we see the radiation pattern for the case when all elements are excited at different frequency.

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This problem could be seen in a different way also,

Alternatively one could also say that, a dipole radiates at a good efficiency when the length and width of the dipole element is optimized according to the desired frequency. So, for each element to radiate at a different frequency, the dimensions(length and width) of the elements should also be different.

I have tried to design a conformal array with 2 elements designed at different frequency. But when I assign the optimized dimensions of the elements(all different dimensions) to the "conformalArray" function, the dimensions become same for all the elements automatically. This is because of the fact that when we use conformal array function we specify a specific frequency.

See the code below.

clc;
clear all;
close all;
%%
freq1 = 500e6;
freq2 = 1e9;
%% Design 
antenna = dipole;
e1 = design(antenna,freq1)

e1 = 
  dipole with properties:

        Length: 0.2818
         Width: 0.0060
    FeedOffset: 0
     Conductor: [1×1 metal]
          Tilt: 0
      TiltAxis: [1 0 0]
          Load: [1×1 lumpedElement]

e2 = design(antenna,freq2)

e2 = 
  dipole with properties:

        Length: 0.1409
         Width: 0.0030
    FeedOffset: 0
     Conductor: [1×1 metal]
          Tilt: 0
      TiltAxis: [1 0 0]
          Load: [1×1 lumpedElement]

%%
c = conformalArray;
ca = design(c,500e6,{e1,e2});
show(ca)

ca.Element(1,1)

ans = 1×1 cell array
    {1×1 dipole}

The dimensions of e1 and e2 are different, but the dimensions of ca.Element(1,1) and ca.Element(1,2); are same.

How do I approach this problem.

Thanks in advance.

Regards,

Biplob Biswas

PhD Research Scholar

[Biplob]

Hello MATLAB Users,

I have figured out a way of doing it using the 2nd alternatice method where each element is optimized for a different frequency and then arranged in an array. Unfortuntely the result which I was expecting is not produced.

As per my common sense the 1st method of feeding each element with a different frequency is an unrealistic approach because we dont feed an antenna with a specific frequency; we optimze the antenna dimensions and substrate parameters to make to resonate at a desired frequency.

I hope this is the correct explaination. Please let me know your views on this.